Friday 1 October 2010 08.04 EDT
First published on Friday 1 October 2010 08.04 EDT

A cutter in an Australian clothing factory changed Morris Gleitzman's life. Disillusioned with education after a miserable time at grammar school, Gleitzman had stopped reading books when he hit 14 and discovered girls, then quit school after O-Levels. He was marking time in the factory, determined never to set foot in another educational establishment, when one morning one of his fellow workers – a man he barely knew – handed him The Horse's Mouth by Joyce Cary. "I started reading it on the way home and within two days I knew I'd taken a wrong turn in my life," he says. "I wanted to be back among people who cared about books."

Forty years on, with more than 30 children's books, numerous screenplays and a bundle of awards to his name (a shortlisting for the Guardian children's fiction prize just the latest) it's hard to believe that the soft-spoken man sipping tea opposite me could ever have been anything other than a writer. Although hoarse from speaking to a huge hall full of children the previous day, he is serious and eloquent about his work and his motivations – especially concerning his novel Now, the last in what is known as Gleitzman's "Holocaust trilogy".

Gleitzman himself seems uncomfortable with the description. "To me they're friendship books, rather than 'Holocaust books'," he says. "Of course, the Holocaust is an all-important context, but if I was only writing about the Holocaust then I think there are historians – and survivors – who have already done it much better than I could and, in terms of the survivors, with more validity. I'd be happy to leave it to them."

As it happens, of the three books, Now has the loosest connection to the second world war: unlike the first two, Once and Then, it takes place in contemporary Australia. Yet still, at its heart, is Felix, the little boy of the first two books, now an old man but still carrying pain and guilt from his early experiences, and his 10-year-old granddaughter, named Zelda after his childhood friend from Once and Then.

The first two books are moving, haunting and funny in almost equal measure, and always gripping as they describe Felix and Zelda's flight from the Nazis and fight to stay alive. The story is told through the eyes of 10-year-old Felix, and the mix of innocence and horror is unsentimental and often heartbreaking. The last chapter of Once begins, "Once I lay in a field somewhere in Poland, not sure if I'm dead or alive. You know how when you jump off a moving train and Nazis shoot at you with machine guns and you see sharp tree stumps coming at you and then you hit the ground so hard you feel like you've smashed your head open and bullets have gone through your chest and you don't survive even though you prayed to God, Jesus, Mary, the Pope and Richmal Crompton? That's what happened to poor Chaya. She's lying next to me on the grass, bleeding and not breathing ... "

Each chapter in the first two books begins with the same unusual construction: a line or two in the past tense, then a shift into the present. It's Gleitzman's attempt to convey, to an audience that has a tendency to "concertina history", that the past is not necessarily a different place in terms of human experience. Ask young people about a world before electricity, he says, laughing, and they immediately talk about people living in caves and roasting bison legs on open fires. His own tendency to forget that, in the past, the grass was green and the sky was blue, was challenged when he visited Auschwitz. What "staggered" him was not so much the obvious monstrosity of it, but the familiarity of the environment, horrific in its ordinariness. "It was like Canberra suburbs," he says, still bemused. "There were the same kind of apartment buildings and grass verges and flowerbeds in the workcamp area. It was just the sheer familiarity of it: that it wasn't this expressionistic nightmare world but real grass and bricks ... "

Although it steers clear of death camp scenes, the ending of Then is devastating, and Gleitzman admits that he needed to take a couple of years off before he could tackle the third book. "Writing stories closely connected to the Holocaust is a tough task, and Then was a particularly emotionally challenging thing because I knew all the way through that I was moving inexorably towards the most difficult thing I'd ever written," he says.

In Now, the "second" Zelda's voice is chirpier, more knowing, than her predecessor's, and although she has to face up to school bullies and catastrophic bush fires, some of the dramatic impact of the first two books is inevitably lost. It is a quieter work, tackling Felix's ongoing guilt 70 years on, and Zelda's complex feelings around being named after someone who occupies such a conflicted place in her grandfather's heart.

"I've always been aware that to be named after someone from the past carries with it all kinds of bittersweetness," explains Gleitzman. "I was named after my Jewish grandfather who left Poland early in the 20th century. What I knew from an early age was that he had lived most of his life in England, his Jewish wife had died and he married a non-Jewish woman who was my grandmother. And so the Jewishness was quite a distant part of my consciousness, as was the connection with Poland and the Holocaust."

It became less distant after he stumbled across the biography of Janusz Korczak, a Polish Jewish doctor and children's author who helped run an orphanage for 200 Jewish children. In 1942 when the Nazis arrived to murder the children, Korsczak was offered his freedom but chose to stay and die with the children rather than abandon them. "He became my hero," says Gleitzman, simply. He also provided Gleitzman with the context for his "friendship book".

"That apparent contradiction – that as a species, we are capable of the very best and the very worst – had fascinated me for a long time," he says. "I'd been thinking for a while that I'd like to write a story about a friendship between two children, because I believe friendship is where we display much of the best that we're capable of. I'd decided that if I wrote about such a friendship, I'd place it in the context of the absolute opposite of human behaviour. Not only do those kinds of dramatic contrasts make for a good story, but if one really wants to test and explore the capacities of friendship and the notion of love being an indestructible thing, to do so in the context of the mass perpetration of some of the most unfriendly behaviour conceivable would be an interesting way of doing it."

Within those contrasts, the story also offered Gleitzman the opportunity to explore another area of interest for him: the potential of stories to contextualise; to show, unflinchingly, all sides of the story. It's a subtlety he feels is missing in the media-drenched world children live in today, in which they're bombarded with "decontextualised fragments of bad news and fleeting figures in soundbites, instantly cast as perpetrators or victims".

That need to avoid snap judgments based on surface impressions and to be more thoughtful, more nuanced about how we react to others, especially "outsiders", is a preoccupation that runs through much of Gleitzman's work. "In several of my books I've explored the capacity of stories to connect readers with characters from other parts of the world with very different surface characteristics to their lives," he says. One such is Boy Overboard, the tale of two Afghan children trying to get to Australia as refugees. "If we get caught up in a story it's because we've started to care about the characters and that can only happen if we've moved beneath the surface. Boy Overboard has become one of those stories that gives young people that shock of realisation of being in the shoes of a character who is totally different from them. That can happen geographically or it can happen with time. All of the surface indicators were that people were different back then because they had weird haircuts and funny clothes, but basically people are always people and the essential parts haven't changed," he says.

Despite his gentle Australian twang, and the bold "G'day" on the front of his website, Gleitzman himself has some experience of being the outsider, from a different part of the world. Although he was born in Lincolnshire, in 1953, and grew up in London, he moved to Australia when he was 16, when his parents decided to emigrate with him and his younger brother and sister. They "destroyed my life", he says with a teenager's sense of drama and a wry smile, noting that he was being dragged away from a girl "who would almost certainly have become my girlfriend in, oh, a matter of weeks" – but after the obligatory spell of "self-righteous sulking" he slowly realised that Australia was not all that bad.

After the epiphany in the factory he crammed two years of further education into the space of eight months and then enrolled on a Professional Writing course at Canberra College, the first of the American-style vocational writing courses at a Australian university. A successful career in screenwriting followed until Gleitzman's path changed again when he was asked to adapt one of his screenplays.

"I did it in the spirit of adventure but quickly realised that I love being boss of the whole process," he says. As an adult writing about young characters, he also takes a very serious view of his obligations towards those characters. "In all of my books I'm taking them on an emotionally challenging and sometimes physically dangerous process with a bit of fun and anarchy along the way. With the power comes responsibility. As a screenwriter you have that sense of responsibility but not the power because others – directors, producers, actors – come in and override the vision. I can carry out my duties better as a novelist," he concludes.

As for Joyce Cary and the perceptive factory worker, Gleitzman still has the battered old Penguin Classics copy of the book but says that he never really managed to thank the older man for how he'd helped him. "It took me quite a few years to realise what he'd done for me that day and by that time I had lost contact with him. In one sense I owe my career more to him than to anyone else".